A rare human G10P[8] rotavirus with a reassortment between bovine and human viruses was detected from a patient with acute gastroenteritis in Vietnam. Genetic analysis using complete coding sequences of all segments showed a genomic constellation of this virus of G10-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Its VP7 region was genetically related to that of a bovine rotavirus derived from Australia (strain VICG10.01), whereas all other genes were identical to those of a human rotavirus derived from Australia (strain Victoria/CK00047). These results indicate a possibility that the reassortment of the rotavirus was caused by immune escape in Australia and the rotavirus was carried to Vietnam. Additionally, this finding will help further understanding the evolution of rotaviruses circulating in Vietnam.

Saccharomyces cerevisiae Mph1 is a 3–5′ DNA helicase, required for the maintenance of genome integrity. In order to understand the ATPase/helicase role of Mph1 in genome stability, we characterized its helicase activity with a variety of DNA substrates, focusing on its action on junction structures containing three or four DNA strands. Consistent with its 3′ to 5′ directionality, Mph1 displaced 3′-flap substrates in double-fixed or equilibrating flap substrates. Surprisingly, Mph1 displaced the 5′-flap strand more efficiently than the 3′ flap strand from double-flap substrates, which is not expected for a 3–5′ DNA helicase. For this to occur, Mph1 required a threshold size (>5 nt) of 5′ single-stranded DNA flap. Based on the unique substrate requirements of Mph1 defined in this study, we propose that the helicase/ATPase activity of Mph1 play roles in converting multiple-stranded DNA structures into structures cleavable by processing enzymes such as Fen1. We also found that the helicase activity of Mph1 was used to cause structural alterations required for restoration of replication forks stalled due to damaged template. The helicase properties of Mph1 reported here could explain how it resolves D-loop structure, and are in keeping with a model proposed for the error-free damage avoidance pathway.

The two endonucleases, Rad27 (yeast Fen1) and Dna2, jointly participate in the processing of Okazaki fragments in yeasts. Mus81–Mms4 is a structure-specific endonuclease that can resolve stalled replication forks as well as toxic recombination intermediates. In this study, we show that Mus81–Mms4 can suppress dna2 mutational defects by virtue of its functional and physical interaction with Rad27. Mus81–Mms4 stimulated Rad27 activity significantly, accounting for its ability to restore the growth defects caused by the dna2 mutation. Interestingly, Rad27 stimulated the rate of Mus81–Mms4 catalyzed cleavage of various substrates, including regressed replication fork substrates. The ability of Rad27 to stimulate Mus81–Mms4 did not depend on the catalytic activity of Rad27, but required the C-terminal 64 amino acid fragment of Rad27. This indicates that the stimulation was mediated by a specific protein–protein interaction between the two proteins. Our in vitro data indicate that Mus81–Mms4 and Rad27 act together during DNA replication and resolve various structures that can impede normal DNA replication. This conclusion was further strengthened by the fact that rad27 mus81 or rad27 mms4 double mutants were synergistically lethal. We discuss the significance of the interactions between Rad27, Dna2 and Mus81–Mms4 in context of DNA replication.

To learn more about risk behaviors among men who have sex with men (MSM) in Vietnam and their prevalence of HIV, we conducted a study among MSM in Ho Chi Minh City (HCMC) to determine HIV-1 prevalence and behaviors associated with infection. This consisted of formative (35 MSM) and cross-sectional (600 MSM) studies at 72 sites, including 75 transvestites, 55 bisexuals, 10 sex workers, and 460 other MSM. Only 5.3% cohabited with a wife/girlfriend, but 30% reported ever having sex with a female. Prevalence of HIV was 8%, ranging from 33% in sex workers to 7% among transvestites and other MSM. Injecting drugs, selling sex, being 20–40 years old, having less than 6 years of education, and having more than five male anal sex partners in the past month were associated with being HIV-infected. MSM are an HIV bridge group, and should be included in sentinel surveillance. Targeted interventions should be implemented.

The non-essential VTS1 gene of Saccharomyces cerevisiae is highly conserved in eukaryotes and encodes a sequence- and structure-specific RNA-binding protein. The Vts1 protein has been implicated in post-transcriptional regulation of a specific set of mRNAs that contains its-binding site at their 3′-untranslated region. In this study, we identified VTS1 as a multi-copy suppressor of dna2-K1080E, a lethal mutant allele of DNA2 that lacks DNA helicase activity. The suppression was allele-specific, since overexpression of Vts1 did not suppress the temperature-dependent growth defects of dna2Δ405N devoid of the N-terminal 405-amino-acid residues. Purified recombinant Vts1 stimulated the endonuclease activity of wild-type Dna2, but not the endonuclease activity of Dna2Δ405N, indicating that the activation requires the N-terminal domain of Dna2. Stimulation of Dna2 endonuclease activity by Vts1 appeared to be the direct cause of suppression, since the multi-copy expression of Dna2-K1080E suppressed the lethality observed with its single-copy expression. We found that vts1Δ dna2Δ405N and vts1Δdna2-7 double mutant cells displayed synergistic growth defects, in support of a functional interaction between two genes. Our results provide both in vivo and in vitro evidence that Vts1 is involved in lagging strand synthesis by modulating the Dna2 endonuclease activity that plays an essential role in Okazaki fragment processing.

Covering soft tissue defects remains challenging for orthopaedic surgeons, especially those in resource-challenged facilities. Covering tissue defects follow a plan from simple to complex: primary closure, local flap, area flap, pedicle flap, and free flap. I will limit my discussion to the role of latter two. At the district-level hospital in Vietnam, pedicle flaps are generally more useful, so I will discuss free flaps only briefly. The choices of pedicle flaps include: kite flap, posterior interosseous flap, radial flap (Chinese flap), neurocutaneous flap, anterolateral thigh fasciocutaneous flap, gastrocnemius flap, sural flap, posterior leg flaps; we typically use a free flap with the latissimus dorsi. Soft tissue coverage with pedicle flaps has many advantages: reliability, relatively easy harvest, and good blood supply. Free flaps with microanastomosis have an important place in covering difficult medium- or large-sized soft tissue defects but also require more instruments and more highly trained surgeons.

Background

The clinical presentation of Bordetella pertussis can overlap with that of respiratory syncytial virus (RSV); however, management differs.

Hypothesis

First, the prevalence of B. pertussis is less than 2% among patients screened for RSV, and second the prevalence of B. parapertussis is also less than 2% among these patients.

Methods

Nasal washings submitted to a clinical laboratory for RSV screening were tested for B. pertussis and B. parapertussis, using species-specific real-time polymerase chain reaction (PCR) assays. These were optimized to target conserved regions within a complement gene and the CarB gene, respectively. A Bordetella spp. genus-specific real-time PCR assay was designed to detect the Bhur gene of B. pertussis, B. parapertussis, and B. bronchiseptica. RSV A and B subtypes were tested by reverse transcription-PCR.

Results

Four hundred and eighty-nine clinical samples were tested. There was insufficient material to complete testing for one B. pertussis, 10 RSV subtype A, and four RSV subtype B assays. Bordetella pertussis was detected in 3/488 (0.6%) (95% CI 0.1% to 1.8%), while B. parapertussis was detected in 5/489 (1.0%) (95% CI 0.3% to 2.4%). Dual infection of B. pertussis with RSV and of B. parapertussis with RSV occurred in two and in three cases respectively. RSV was detected by PCR in 127 (26.5%).

Conclusion

The prevalence of B. pertussis in nasal washings submitted for RSV screening was less than 2%. The prevalence of parapertussis may be higher than 2%. RSV with B. pertussis and RSV with B. parapertussis coinfection do occur.

Aichi virus is a new member of the family Picornaviridae, genus Kobuvirus, and is associated with human gastroenteritis. This study detected Aichi virus in 28 of 912 fecal specimens which were negative for rotavirus, adenovirus, norovirus, sapovirus, and astrovirus and were collected in Japan, Bangladesh, Thailand, and Vietnam during 2002 to 2005.

Objective

Lack of representative data about hidden groups, like men who have sex with men (MSM), hinders an evidence-based response to the HIV epidemics. Respondent-driven sampling (RDS) was developed to overcome sampling challenges in studies of populations like MSM for which sampling frames are absent. Internet-based RDS (webRDS) can potentially circumvent limitations of the original RDS method. We aimed to implement and evaluate webRDS among a hidden population.

Methods and Design

This cross-sectional study took place 18 February to 12 April, 2011 among MSM in Vietnam. Inclusion criteria were men, aged 18 and above, who had ever had sex with another man and were living in Vietnam. Participants were invited by an MSM friend, logged in, and answered a survey. Participants could recruit up to four MSM friends. We evaluated the system by its success in generating sustained recruitment and the degree to which the sample compositions stabilized with increasing sample size.

Results

Twenty starting participants generated 676 participants over 24 recruitment waves. Analyses did not show evidence of bias due to ineligible participation. Estimated mean age was 22 years and 82% came from the two large metropolitan areas. 32 out of 63 provinces were represented. The median number of sexual partners during the last six months was two. The sample composition stabilized well for 16 out of 17 variables.

Conclusion

Results indicate that webRDS could be implemented at a low cost among Internet-using MSM in Vietnam. WebRDS may be a promising method for sampling of Internet-using MSM and other hidden groups.